msm: kgsl: For MMU fault do not clear pending VBIF transactions

MMU fault could cause VBIF to hang. When VBIF is hung trying to
clear pending VBIF transactions will fail. For MMU fault first check
for MMU fault and do a hard reset instead of trying to clear VBIF
pending transactions.

Change-Id: Ief6be0a3d8d91a2516e08382b36ebebd2f703ef6
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>